Dobby chain bar and linkage



Nov. 12, 1963 w. a. HARRIS DOBBY CHAIN BAR AND LINKAGE Filed Aug. 21,1962 z'yf.

INVENTOR. warren. B. Hon-r- L5 BY C United States Patent $110,328 DQBBYCHAIN BAR AND LHNKAGE Warren B. Harris, 6 Summer St, Millhury, Mass.Filed Aug. 21, 1962, Ser. No. 218,323 1 Claim. (1. 139-334) controllingthe cloth pattern. Each bar is usually provided with one or two rows ofclosely spaced holes into which threaded metal pegs are screwed. Thesepegs are removably mounted in the various holes as required by the clothpattern. The standard linkage comprises, as shown in FIG. 4 of thedrawings, an S-shaped wire mounted in a hole in each bar, and the freeends of the link either touch or are embedded only slightly in the barstructure. However, the bar in cross-section has the shape of a frustumso that there is but little material in the bar structure to support thelink strongly and prevent it from moving in its setting when understress, and thus either breaking or damaging the bar structure and sointerfering with the loom operation. This is particularly true where thebar is made of wood which is readily split by any twisting of theS-shaped link from its initial position. If the bar is made of a moldedplastic, the loop end of the S-shaped link it not adequately supported,since the straight run of the link must be between the adjacent barholes, and the free end of the loop is necessarily located in that wedgeshaped bar close to one of the holes; the link, therefore, cannot beembedded adequately in the plastic material.

The primary object of this invention is to overcome the above-specifiedproblem and to provide a bar structure which will hold each linksecurely and immovably positioned and thereby form a longer lived andstronger dobby chain bar. Further objects will be apparent in thefollowing disclosure.

Referring to the drawings illustrating a preferred embodiment of theinvention and a prior art form:

PEG. 1 is a fragmentary perspective view of one end of the bar;

FIG. 2 is a plan view, partly broken away, of two of the bars connectedtogether by a linkage;

FIG. 3 is an end view of one of the bars; and

FIG. 4 is a fragmentary plan view of the ends of two standard woodenbars of the prior art.

Referring first to FIG. 4, the standard wooden bar as heretofore madecomprises a wedged-shaped bar of wood, which may also have been made ofmolded plastic. The linkage comprises an S-shaped wire 12 passed throughan obliquely arranged hole 13 located between the two rows of staggereddobby pin holes 14. After a straight wire has been passed through thehole 13, its two free ends 15 are bent downward into contact with thewood. The ends are interconnected by a chain link 16 to make an endlesschain structure. If the bar is made of a molded plastic, these ends maybe slightly embedded therein, but as is obvious from inspection of thedrawing, these free ends are necessarily close to an adjacent peg hole14 and so are not adequately embedded and supported against any turningor twisting action, with a resultant impairment of the structure underany lateral stress.

In accordance with my invention, as shown in FIGS.

djihfiz Patented Nov. 12, 1963 "ice 1, 2, and 3 of the drawings, I formthe dobby chain bar of a suitable molded thermo-plastic or thermosettingplastic resinoid, such as a vinyl resin, polyethylene, celluloseacetate, a phenol-formaldehyde condensation product or other suitablematerial of adequate strength and wearability which is capable of beingcast or molded to the required narrow elongated wedge shape by heatand/or pressure. The linkages 20, located near the bar ends arepreferably made of wire and have a substantially S-shaped configuration.These are preferably shaped initially in their final forms and thus donot require a separate manual operation for shaping the loop ends afterassembling the linkage wire. These shaped pieces are properly mounted inthe mold, after which the resinoid is cast or molded around the wire inposition to hold the wire. The central portion 21 of the link isproperly shaped for location between the adjacent dobby peg holes 22formed in the bar so as not to interfere with removably mount ing a setof screw threaded pegs 23 in selected holes of the bar. Reference may behad to my prior patents for a showing of the structure of the pegs whichare arranged to project from the wide top face of the bar. Each linkterminates in two oppositely projecting loops similar to loop 12 of FIG.4 to which intermediate links are connected. The bar is illustrated ashaving two rows of peg holes in a staggered arrangement, but for someuses only one row of holes is required. The pegs project outwardly fromthe wide face of the bar and the narrow face parallel to the top is freefor riding in the cylinder groove.

As a simple and adequate structural feature for supporting the linkagewire, I propose to shape the bar adjacent each of the linkage wires 20so as to provide a large linkage strengthening mass of the moldedmaterial which will embed a substantial proportion of the wire thereinand hold it immovably positioned. To this end, I provide the bar with anenlarged portion 24, preferably of substantially rectangular crosssection, as shown in FIG. 3, which builds up the otherwise wedged shapedbar only adjacent to the link wire 20. The major portion of the bar isshaped as a frustum of a narrow elongated wedge and its converging sidefaces 25 (FIG. 1) are shaped to interfit with grooves and teeth on thedriving cylinder, and there is usually room on the latter for theseenlarged portions 24 to pass around the cylinder. Or, if desired, thecylinder may be cut away adjacent these short portions 24 to provideclearance therefor.

It will be seen by inspection of FIG. 3 that each end of the link wireis shaped as a loop and that the free end 26 extends to a considerabledistance into the substance of the rectangular portion 24 of the barwithout interfering with the dobby peg hole 22. If the enlarged portion24 were omitted, the wire end could project into the bar only to aslight extent below the surface 25. Because of the added substance inthe bar portion 24, the looped end of the wire is held securely inposition by the large 7 mass of that molded resinoid and it cannot twistfrom its initial position. The link wires 20 are suitably connected bythe links 28 (FIG. 2) and the dobby bar chain is adequately strong tosatisfy all of its required functions of controlling the cloth pattern.

The portion 24 which embeds the wire linkage is shown as rectangular intransverse cross section with its lateral dimension equal to thethickness of the bar between the wide top face 28 and the narrow bottomface 29 of the bar (FIG. 3). The Width of the portion 24 is the same asthe breadth of the wide face 28 of the bar. The length of the portion 24longitudinally of the bar is preferably only a little more than theexternal diameter of the loop of the wire but long enough to giveadequate support to the wire loop and yet it is short enough so that itwill not strike the cylinder teeth and interfere with the normal use ofthe frustum portion of the bar between the faces 25 which drive thedobby chain. A preferred shape of bar which is usually about 8 or 10inches long has its wide face 23 about /8 inch wide and its narrow faceabout inch wide, and the wedge bar is about inch thick. The projection24 has a length of about /2 inch, which embeds adequately a wire loop ofabout inch external diameter. However, these dimensions may be changedwithin the scope of this invention, and particularly the corners andedges may be rounded. It will be appreciated also that the shapes andtypes of bar and linkage materials employed rnay be varied, as deemednecessary.

According to this invention, the linkage has a central link portionfully embedded in the wedge shaped bar substance and two looped shapedends projecting oppositely, and wherein the loop ends are firmlyembedded in enlarged laterally projecting portions of the bar which areno wider than the Width of the top face of the bar and have the samethickness as the bar, whereby the loop may have its end firmly securedin place Without interfering with the adjacent dobby pegs. The link 20is preshaped of a hard drawn steel wire of high tensile strength, asdistinguished from Wire heretofore used which had to be soft or annealedso that it could be readily bent into the required end loop shape afterit had been assembled in the bar. Because a dobby chain may have a verygreat length, this prior use of a soft steel link has often resulted ina chain loop straightening out and the chain breaking apart. Myprefabricated steel link of high strength avoids this problem. Otheradvantages in this new construction Will be apparent.

It is to be understood that the above disclosure of a preferredembodiment is not to be interpreted as imposing limitations on theappended claim.

4 I claim: A dobby chain comprising a set of parallel cross bars andinterconnecting linkages, each bar being a body of a molded resinoidhaving its major portion shaped as a frustum of a narrow elongated wedgehaving parallel wide and narrow faces, said bar having at least one rowof spaced peg holes, and dobby pegs removably mounted in selected pegholes and projecting laterally from the wide face of the bar, saidlinkage including an S-shaped hard drawn steel wire link of high tensilestrength having a central portion embedded between adjacent peg holes inthe bar near each end thereof and two projecting end loops terminatingin free ends, said bar having near each end a linkage strengtheningprojecting portion of substantially rectangular cross-sectiontransversely of the bar whose side faces lie substantially in the planesof said parallel bar faces and its lateral dimensions are substantiallyequal to the cross sectional width and breadth of the bar,

' said link end loops projecting oppositely with said free endspermanently and deeply embedded in said strengthenin-g projectingportions of the resinoid body near to but not intersecting dob'by pegholes, and said strengthening portions extending longitudinally of thebar only sufficient to embed and support the loop ends firmly withoutinterfering with the normal useof the bar.

References Cited in the file of this patent UNITED STATES PATENTS

